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Controlled pressure casting of tibial fractures: a preliminary report
Injury. 13.27-33
PrintedinGreatBritain
27
Controlled pressure casting of tibia1 fractures: a preliminary report A. F. Bedford and J. C. Angel Royal National Orthopaedic Hospital, Stanmore
Summary
PATIENTS
A new method for the application
The cast was applied when the fracture was clinically stable, i.e. when there were only a few degrees of movement at the fracture site. The average interval between fracture and application ofa pressure cast was 8.5 weeks (range I-1 3 weeks) in the 19 patients treated for fractures not complicated by a delay in union (‘fresh fractures’). Stockinet and tubigrip were applied to the limb. Two layers of plaster bandage from a 36-inch roll were then cut in the manner of a Sarmiento template (Fig. 4) allowing generous margins. The plaster cut-out was immersed in cold water and applied over the leg. A thin plastic bag was then applied to the limb so that its opening lay above the knee. A Sterishield bag connected to an air compressor was then applied over the plastic bag and the air pressure raised to 25-30 mm Hg. The Sterishield bag has a proximal valve which closes when filled with air so that the pressure within the bag can be kept relatively constant but without any tourniquet effect (Fig. 5). The raised air pressure within the Sterishield bag compresses the inner plastic bag and thereby the plaster against the limb. In this way the plaster conforms accurately to the skin surface. After 4 to 5 minutes. the plaster was dry and the air pressure was reduced following which both bags were removed. This thin plaster shell was then reinforced and after trimming to allow full knee and ankle movement. an appropriate heel cup was applied. The whole procedure takes approximately I5 minutes. The patient was advised to wear a shoe one half size larger than usual to accommodate the heel cup. Alternatively, if the patient prefers he may split
of a Sarmiento below-knee plaster brace is described together with the results of its use in 22 fractures of the shaft of the tibia. Adequate control of the fractures was obtained and the rate of union appeared satisfactory. The range of movement of the knee and ankle at the time of removal of the cast were more than two-thirds the normal range in respectively 90 per cent and 80 per cent of fractures of the tibia so treated. Consequently, the need for physiotherapy was reduced.
INTRODUCTION
pressure casting of plaster-of-Paris was originated by the Biomechanical Research and Development Unit at Roehampton for the casting of amputation stumps. We have adapted the technique to the application of a Sarmiento cast-brace. The plaster that results conforms accurately to the shape of the limb from knee to ankle. It is separated from the skin only by a layer of stockinet and another of tubigrip. Tubigrip helps control oedema of the foot and ankle, both of which are unsupported by plaster but restrained by a polythene heel cup (Fig. 1). The inner surface of the cast is extremely smooth in comparison with those conventionally applied (Fig. 2). The cast has no high pressure areas in contrast to those which result when plaster bandage is wound about a limb with a variable curvature (Fig. 3). Early movement of the knee and ankle is possible and the patient can walk with a more normal pattern. It is possible to clean the foot and this must be done daily to prevent maceration of the skin of the heel within the plastic heel cup. CONTROLLED
AND
METHODS
Injury: the British Journal of Accident Surgery Vol 1 ~/NO. 1
28
b
a
Fig.
I. a and
b, The
controlled
pressure
cast.
the heel of the shoe upper and lace this separately. Twenty-two patients, 18 men and 4 women, have been treated with this technique from April 1977 to October 1978. The average age was 26.8 years with a range of 14-67 years (Fig. 6). Level of fracture
The shaft of the tibia was divided into three equal parts and fractures classified by these zones or junctional areas. Twelve fractures were at the junction of the middle and distal thirds, and 2 in the distal third of the tibia. The remaining 8 fractures occurred in the middle third of the tibia including I segmental fracture. Six of the tibia1 fractures had no associated fracture of the frbula although in one case considerable overlap of a segmental fracture of the tibia suggested disruption of one of the tibiofrbular joints. Nature
remaining case was left open to granulate after wound excision. The nature of the fractures is shown in Table I and it is noticeable that the majority were initially unstable. Associated
injuries
One fracture of the tibia was associated with a fracture of the ipsilateral femoral shaft, which had been fixed by a Kiintscher nail. Three patients had associated fractures of the contralateral tibia. Of these one was plated using A0 techniques, a second lay in the proximal third of the tibia and was treated by cast-bracing using polycentric knee hinges. The third patient had severe ischaemia for which below-knee amputation was necessary. A further patient had associated fractures of the contralateral femur and ankle which required internal fixation using a Kiintscher nail and screws. Five of the patients had associated minor head injuries.
of the fractures
Six of the fractures were initially compound and all but one were treated by conventional primary wound excision and suture. The
Cause
of the injuries
The activity in Fig. 7.
preceding
the fracture
is indicated
29
Bedford and Angel: Controlled Pressure Casting Tab/e
1. Nature
of fractures
in
22
patients treated” Type of fracture
Number
Greenstick Transverse Short oblique Spiral Segmental Cornminuted ‘Simple,
16; compound, 6.
pin was necessary in 4 patients because of instability of the reduction. Three of the fractures were treated by A0 compression plating because of loss of position before coming under our care. Two of these patients were referred because the fractures had developed infected non-union. In one patient the interval between fracture and pressure casting was 131 weeks and this fracture had failed to unite even after two previous bone grafts. In the second case the interval was 77 weeks. Fibular osteotomy was performed in 8 patients during treatment by pressure casting. In 4 cases it was done early to allow impaction of the fracture site, or correct a tendency to recurrent varus angulation. In the remainder the osteotomy was performed after I2 weeks when union was thought to be slow.
a
RESULTS
b
Irregularity of the inner surface of a conventionally applied plaster contrasted with b. that of controlled pressure casting. Fig.
2.
a,
Treatment casting
Sixteen
of
fractures
of the fractures
before
were displaced
pressure sufflci-
ently to require manipulation under anaesthesia and in some instances this was repeated on two or more occasions. Traction using an OS calcis
Twenty-one of the 22 fractures in 22 patients have been followed to union. The remaining patient is still under treatment for non-union of a severe fracture initially associated with severe soft tissue loss. This patient had also sustained a severe injury of the other limb which necessitated below-knee amputation. The average interval from fracture to union in the I9 ‘fresh fractures’ was 17.7 weeks (range 6-37 weeks). The cast was removed when the patient could walk with an even cadence gait. Clinical and early radiological union was invariably present at this time. The average period spent in the pressure cast was 9.7 weeks (range 3-26 weeks), excluding the 3 cases treated for a delay in union. Of these, 2 fractures have united after 6 and 73 weeks of pressure cast treatment. After removal of the cast the patient was encouraged to walk with two sticks, taking as much weight on the leg as was comfortable.
30
Injury. the British Journal of Accident Surgery Vol. 1 ~/NO.
Zone of High Pressure
Tibia Deep Fascia I nterosseous
Membrane
Fibula Skin
Fix.
3. Cross-section
of the calf
showing the high pressure zone produced
by
rolling on a plaster bandage.
Fi
used
for cutting the initial plaster template.
The angulation of each fracture was measured on radiographs taken in two planes before application of our cast and at union. These were compared and were found to be less than 2”. At union, 7 fractures showed perfect alignment in the lateral view and 2 in anteroposterior radiographs. Nine fractures showed anterior bowing (average 5” with a range of 2-10”). and 9 fractures posterior bowing with an average of 4.3” (range 2-10”). Seven fractures showed varus angulation with an average of 4.3” (range l-8”) and a further 6 fractures showed valgus angula-
tion with an average of 4” (range 2-S”). Marked rotatory mal-union was not found. The length of the lower limbs was compared clinically and by scanograms, and the average shortening at union was found to be 4.5 mm (range O-l 5 mm). Twenty of the 22 patients found the cast more comfortable than their previous above-knee non-weight-bearing padded plaster-of-Paris casts. No patient found this shorter cast less comfortable and surprisingly only 2 found it less supporting than the above-knee plaster cast.
1
Bedford
and Angel:
Controlled
Pressure
Valve
Plaster-of-Paris
Sterishield Fig.
10 9
31
Casting
5. Diagrammatic
Plastic
Bag
representation
ofthe
controlled
r
8
pressure
of
B
I-l
98-
6 5 _ Number Patients
of
6 5 -
-
4-
2-
-
2-
1
0 O-9
lo-19 20-29 30-3940-49
50-5960-69
ofthe
patients
O-
treated
Fig. 7. Joint movement
The range of movement of the knee and ankle at removal of the controlled pressure cast is given in Table II. It can be seen that only 2 patients showed less than half the normal range of knee movement at the time of removal of plaster. One of these patients had a fracture of the shaft of the ipsilateral femur which had been fixed with a Kiintscher nail. Knee movement became full within 2 months in all cases. Sixteen of 21 patients (76 per cent) had greater than two-thirds of the normal range of movement at the ankle.
Motor Cycle
l-
70+
Age in Years distribution
Pedestrian Hit by Car
3-
l-
Age
Car
7 -
3-
6.
system.
10 -
Male Female
4-
Fig
casting
11 -
7Number Patients
Bag
Activity
Soort
which
RTA SKate Board Activity at Time of
precipitated
Fall
Injury
injury.
No association between stiffness of the ankle and either flbular osteotomy or calcaneal traction was found. Twelve ofthe 2 I patients (57 per cent) showed more than half the normal range of movement at the subtalar joint when the controlled pressure cast was removed. Those patients with a smaller range of movement had either sustained very severe injuries to the tibia or had undergone prior internal fixation of the limb. Only 3 patients required physiotherapy either during or after removal of this cast. Exercises for the knee
32
Injury: the British Journal of Accident
Tab/e//.
Range
Joint
Knee Ankle Subtalarjoint
of movement
at the removal
Full
17 13 -
of the controlled
pressure
cast in the 2 1
Range of movement Greater than Between one-half two-thirds normal and two-thirds range normal range
2 3 6
were required in 1 patient following femoral shaft fracture. A second patient had a fixed equinus deformity associated with an infected when treatment by controlled non-union pressure casting was started. His ankle responded to physiotherapy with full weightbearing within the functional cast. and at union he had a plantigrade foot with half the normal range of movement at the ankle. Oedema of the foot and ankle was surprisingly mild both with, and after, removal ofthe plaster. Complications
One patient suffered a further road traffic accident that refractured his tibia 2 weeks after removal of his cast. His initial fracture had been plated and the plate subsequently fractured before union was obtained. DISCUSSION
The aim of treatment of any fracture of the shaft of the tibia is union with a satisfactory length and alignment of the limb and a useful range of movement of the knee, ankle and foot. Until recent years traditional methods have required prolonged periods in plaster-of-Paris from toe to groin as advocated by Watson-Jones (1976) in order to reduce stresses, particularly those of rotation, on the fracture site. It is, however, well established that even an expertly applied padded plaster-of-Paris cast allows some movement and angulation of an unstable fracture. Stiffness of the knee is commonly seen after removal of above-knee plasters, but fortunately it is usually temporary. However, stiffness of the ankle and subtalar joint are often a greater problem (McMaster, 1976). The proponents of internal fixation of fractures point to the excellent function that can be obtained by early movement of the knee, ankle and subtalar joints. Unfortunately, internal fixation is not without risk, and there is an appreciable risk of infection, which may delay union or have even worse consequences.
3 6
Surgery Vol. 1 ~/NO.
cases
followed
1
to union
Less than onehalf normal range
2 2 9
The 2 patients with established non-union in this series had both been treated by internal frxation of their fractures before coming under our care. The extent of any joint stiffness has been shown to be closely related to the severity of the fracture (Ellis, 1958) and the rate of union is almost certainly delayed by rigid internal ftxation (McKibbin, 1978). After a fracture of the shaft of the tibia, shortening of the limb may be prevented by bony contact in a stable fracture or by the intact ftbres of the damaged interosseous membrane in the unstable type (Sarmiento et al., 1974). If the fractured tibia and its related muscles are surrounded by a relatively rigid sheath of plaster-of-Paris, the limb is thought to behave as a fluid-filled cylindrical balloon. Shortening of the cylinder cannot occur without an associated increase in the diameter because fluids are incompressible, and this is prevented by the plaster-of-Paris carapace. The plaster-of-Paris cast also maintains alignment (Sarmiento et al., 1974). Sarmiento has used unpadded, below-knee, patellar-tendon-bearing plaster casts, and more recently thermoplastic braces for 482 tibia1 fractures, and has allowed full weight bearing from an early stage. In his series (Sarmiento, 1974) there were only two non-unions and the functional results appeared adequate. However, such a cast or brace is difficult to apply and the patellar-tendon-bearing factor does not appear of great importance in unloading the fracture (Posival. 1973). The method of application of our modiftcation is simple and utilizes plaster with its known excellent properties. Plaster-of-Paris avoids the skin maceration seen under thermoplastic materials. It requires little skill in application contrasting with that necessary for the correct application of a Sarmiento plaster cast. The cast also has a very smooth inner surface and therefore the skin is not at risk (Fig. 2). It provides the closest possible ftt to the limb and therefore
33
Bedford and Angel: Controlled Pressure Casting
theoretically should give the best possible control of the fracture. The results of this admittedly small series indicate that adequate control of both alignment and rotation can be obtained whilst allowing mobilization of the ankle and knee at an early stage in the treatment of tibia1 shaft fractures. Functional use may itself improve the blood supply to the limb and therefore the fracture (Trueta, 1974) and improve healing (Sarmiento, 1974). In this way ‘fracture disease’ has been avoided without the use of internal fixation. It has been especially useful in the treatment of non-union refractory to bone grafting and may prove to be a useful adjunct in the treatment of fractures by electrical stimulation.
theatre at the same hospital for their continuing help.
REFERENCES
Ellis H. (1958) Disabilities after tibia1 shaft fractures. J. Bone Joint Surg. 40B, 190. McKibbin B. (1978) The biology of fracture healing in long bones. J. Bone Joint Surg. 60B, 150. McMaster M. (1976) Disability of the hindfoot after fracture of the tibia1 shaft. J. Bone Join? Surg. 58B, 90.
R. A. (1973) A Measurement System .for Determination of Tibia1 Fracture Brace Force Diswibution. University of Miami, Department of
Posival
Bioengineering. Sarmiento A., Latta L., Zilioli A. et al. (1974) The role of the soft tissues in stabilization of tibia1 fractures. Clin. Orthop. 105, 116.
Acknowledgements
We wish to thank the orthopaedic surgeons of the Royal National Orthopaedic Hospital, Stanmore, for allowing us to report cases which were under their care, and the staff of the plaster
Sarmiento A. (I 974) Functional bracing of tibia1 shaft fractures. Clin. Orthop. 105,202. Trueta J. (1974) Blood supply and the rate of healing of tibia1 fractures. Clin. Orthop. 105, 11. Watson-Jones R. W. (1976) In: Wilson J. N. (ed.) Fracture and Joint Injuries. Edinburgh, ChurchillLivingstone, p. 1075.
Requesls for reprints should be addressed ro: Mr A. F. Bedford, Orthopaedic Department, Central Middlesex Hospital, Acton Lane, London NW 10 7NS.
PROFESSOR
WILLIAM
GISSANE
1898-l
981
Professor Gissane died on I April 1981 on the fortieth anniversary of the establishment of the Birmingham Accident Hospital, with which his name will always be linked. We are not publishing a biographical note because his achievements were fully described by the then Vice-Chancellor ofBirmingham University in Injury 10,5.
PrintedinGreatBritain
27
Controlled pressure casting of tibia1 fractures: a preliminary report A. F. Bedford and J. C. Angel Royal National Orthopaedic Hospital, Stanmore
Summary
PATIENTS
A new method for the application
The cast was applied when the fracture was clinically stable, i.e. when there were only a few degrees of movement at the fracture site. The average interval between fracture and application ofa pressure cast was 8.5 weeks (range I-1 3 weeks) in the 19 patients treated for fractures not complicated by a delay in union (‘fresh fractures’). Stockinet and tubigrip were applied to the limb. Two layers of plaster bandage from a 36-inch roll were then cut in the manner of a Sarmiento template (Fig. 4) allowing generous margins. The plaster cut-out was immersed in cold water and applied over the leg. A thin plastic bag was then applied to the limb so that its opening lay above the knee. A Sterishield bag connected to an air compressor was then applied over the plastic bag and the air pressure raised to 25-30 mm Hg. The Sterishield bag has a proximal valve which closes when filled with air so that the pressure within the bag can be kept relatively constant but without any tourniquet effect (Fig. 5). The raised air pressure within the Sterishield bag compresses the inner plastic bag and thereby the plaster against the limb. In this way the plaster conforms accurately to the skin surface. After 4 to 5 minutes. the plaster was dry and the air pressure was reduced following which both bags were removed. This thin plaster shell was then reinforced and after trimming to allow full knee and ankle movement. an appropriate heel cup was applied. The whole procedure takes approximately I5 minutes. The patient was advised to wear a shoe one half size larger than usual to accommodate the heel cup. Alternatively, if the patient prefers he may split
of a Sarmiento below-knee plaster brace is described together with the results of its use in 22 fractures of the shaft of the tibia. Adequate control of the fractures was obtained and the rate of union appeared satisfactory. The range of movement of the knee and ankle at the time of removal of the cast were more than two-thirds the normal range in respectively 90 per cent and 80 per cent of fractures of the tibia so treated. Consequently, the need for physiotherapy was reduced.
INTRODUCTION
pressure casting of plaster-of-Paris was originated by the Biomechanical Research and Development Unit at Roehampton for the casting of amputation stumps. We have adapted the technique to the application of a Sarmiento cast-brace. The plaster that results conforms accurately to the shape of the limb from knee to ankle. It is separated from the skin only by a layer of stockinet and another of tubigrip. Tubigrip helps control oedema of the foot and ankle, both of which are unsupported by plaster but restrained by a polythene heel cup (Fig. 1). The inner surface of the cast is extremely smooth in comparison with those conventionally applied (Fig. 2). The cast has no high pressure areas in contrast to those which result when plaster bandage is wound about a limb with a variable curvature (Fig. 3). Early movement of the knee and ankle is possible and the patient can walk with a more normal pattern. It is possible to clean the foot and this must be done daily to prevent maceration of the skin of the heel within the plastic heel cup. CONTROLLED
AND
METHODS
Injury: the British Journal of Accident Surgery Vol 1 ~/NO. 1
28
b
a
Fig.
I. a and
b, The
controlled
pressure
cast.
the heel of the shoe upper and lace this separately. Twenty-two patients, 18 men and 4 women, have been treated with this technique from April 1977 to October 1978. The average age was 26.8 years with a range of 14-67 years (Fig. 6). Level of fracture
The shaft of the tibia was divided into three equal parts and fractures classified by these zones or junctional areas. Twelve fractures were at the junction of the middle and distal thirds, and 2 in the distal third of the tibia. The remaining 8 fractures occurred in the middle third of the tibia including I segmental fracture. Six of the tibia1 fractures had no associated fracture of the frbula although in one case considerable overlap of a segmental fracture of the tibia suggested disruption of one of the tibiofrbular joints. Nature
remaining case was left open to granulate after wound excision. The nature of the fractures is shown in Table I and it is noticeable that the majority were initially unstable. Associated
injuries
One fracture of the tibia was associated with a fracture of the ipsilateral femoral shaft, which had been fixed by a Kiintscher nail. Three patients had associated fractures of the contralateral tibia. Of these one was plated using A0 techniques, a second lay in the proximal third of the tibia and was treated by cast-bracing using polycentric knee hinges. The third patient had severe ischaemia for which below-knee amputation was necessary. A further patient had associated fractures of the contralateral femur and ankle which required internal fixation using a Kiintscher nail and screws. Five of the patients had associated minor head injuries.
of the fractures
Six of the fractures were initially compound and all but one were treated by conventional primary wound excision and suture. The
Cause
of the injuries
The activity in Fig. 7.
preceding
the fracture
is indicated
29
Bedford and Angel: Controlled Pressure Casting Tab/e
1. Nature
of fractures
in
22
patients treated” Type of fracture
Number
Greenstick Transverse Short oblique Spiral Segmental Cornminuted ‘Simple,
16; compound, 6.
pin was necessary in 4 patients because of instability of the reduction. Three of the fractures were treated by A0 compression plating because of loss of position before coming under our care. Two of these patients were referred because the fractures had developed infected non-union. In one patient the interval between fracture and pressure casting was 131 weeks and this fracture had failed to unite even after two previous bone grafts. In the second case the interval was 77 weeks. Fibular osteotomy was performed in 8 patients during treatment by pressure casting. In 4 cases it was done early to allow impaction of the fracture site, or correct a tendency to recurrent varus angulation. In the remainder the osteotomy was performed after I2 weeks when union was thought to be slow.
a
RESULTS
b
Irregularity of the inner surface of a conventionally applied plaster contrasted with b. that of controlled pressure casting. Fig.
2.
a,
Treatment casting
Sixteen
of
fractures
of the fractures
before
were displaced
pressure sufflci-
ently to require manipulation under anaesthesia and in some instances this was repeated on two or more occasions. Traction using an OS calcis
Twenty-one of the 22 fractures in 22 patients have been followed to union. The remaining patient is still under treatment for non-union of a severe fracture initially associated with severe soft tissue loss. This patient had also sustained a severe injury of the other limb which necessitated below-knee amputation. The average interval from fracture to union in the I9 ‘fresh fractures’ was 17.7 weeks (range 6-37 weeks). The cast was removed when the patient could walk with an even cadence gait. Clinical and early radiological union was invariably present at this time. The average period spent in the pressure cast was 9.7 weeks (range 3-26 weeks), excluding the 3 cases treated for a delay in union. Of these, 2 fractures have united after 6 and 73 weeks of pressure cast treatment. After removal of the cast the patient was encouraged to walk with two sticks, taking as much weight on the leg as was comfortable.
30
Injury. the British Journal of Accident Surgery Vol. 1 ~/NO.
Zone of High Pressure
Tibia Deep Fascia I nterosseous
Membrane
Fibula Skin
Fix.
3. Cross-section
of the calf
showing the high pressure zone produced
by
rolling on a plaster bandage.
Fi
used
for cutting the initial plaster template.
The angulation of each fracture was measured on radiographs taken in two planes before application of our cast and at union. These were compared and were found to be less than 2”. At union, 7 fractures showed perfect alignment in the lateral view and 2 in anteroposterior radiographs. Nine fractures showed anterior bowing (average 5” with a range of 2-10”). and 9 fractures posterior bowing with an average of 4.3” (range 2-10”). Seven fractures showed varus angulation with an average of 4.3” (range l-8”) and a further 6 fractures showed valgus angula-
tion with an average of 4” (range 2-S”). Marked rotatory mal-union was not found. The length of the lower limbs was compared clinically and by scanograms, and the average shortening at union was found to be 4.5 mm (range O-l 5 mm). Twenty of the 22 patients found the cast more comfortable than their previous above-knee non-weight-bearing padded plaster-of-Paris casts. No patient found this shorter cast less comfortable and surprisingly only 2 found it less supporting than the above-knee plaster cast.
1
Bedford
and Angel:
Controlled
Pressure
Valve
Plaster-of-Paris
Sterishield Fig.
10 9
31
Casting
5. Diagrammatic
Plastic
Bag
representation
ofthe
controlled
r
8
pressure
of
B
I-l
98-
6 5 _ Number Patients
of
6 5 -
-
4-
2-
-
2-
1
0 O-9
lo-19 20-29 30-3940-49
50-5960-69
ofthe
patients
O-
treated
Fig. 7. Joint movement
The range of movement of the knee and ankle at removal of the controlled pressure cast is given in Table II. It can be seen that only 2 patients showed less than half the normal range of knee movement at the time of removal of plaster. One of these patients had a fracture of the shaft of the ipsilateral femur which had been fixed with a Kiintscher nail. Knee movement became full within 2 months in all cases. Sixteen of 21 patients (76 per cent) had greater than two-thirds of the normal range of movement at the ankle.
Motor Cycle
l-
70+
Age in Years distribution
Pedestrian Hit by Car
3-
l-
Age
Car
7 -
3-
6.
system.
10 -
Male Female
4-
Fig
casting
11 -
7Number Patients
Bag
Activity
Soort
which
RTA SKate Board Activity at Time of
precipitated
Fall
Injury
injury.
No association between stiffness of the ankle and either flbular osteotomy or calcaneal traction was found. Twelve ofthe 2 I patients (57 per cent) showed more than half the normal range of movement at the subtalar joint when the controlled pressure cast was removed. Those patients with a smaller range of movement had either sustained very severe injuries to the tibia or had undergone prior internal fixation of the limb. Only 3 patients required physiotherapy either during or after removal of this cast. Exercises for the knee
32
Injury: the British Journal of Accident
Tab/e//.
Range
Joint
Knee Ankle Subtalarjoint
of movement
at the removal
Full
17 13 -
of the controlled
pressure
cast in the 2 1
Range of movement Greater than Between one-half two-thirds normal and two-thirds range normal range
2 3 6
were required in 1 patient following femoral shaft fracture. A second patient had a fixed equinus deformity associated with an infected when treatment by controlled non-union pressure casting was started. His ankle responded to physiotherapy with full weightbearing within the functional cast. and at union he had a plantigrade foot with half the normal range of movement at the ankle. Oedema of the foot and ankle was surprisingly mild both with, and after, removal ofthe plaster. Complications
One patient suffered a further road traffic accident that refractured his tibia 2 weeks after removal of his cast. His initial fracture had been plated and the plate subsequently fractured before union was obtained. DISCUSSION
The aim of treatment of any fracture of the shaft of the tibia is union with a satisfactory length and alignment of the limb and a useful range of movement of the knee, ankle and foot. Until recent years traditional methods have required prolonged periods in plaster-of-Paris from toe to groin as advocated by Watson-Jones (1976) in order to reduce stresses, particularly those of rotation, on the fracture site. It is, however, well established that even an expertly applied padded plaster-of-Paris cast allows some movement and angulation of an unstable fracture. Stiffness of the knee is commonly seen after removal of above-knee plasters, but fortunately it is usually temporary. However, stiffness of the ankle and subtalar joint are often a greater problem (McMaster, 1976). The proponents of internal fixation of fractures point to the excellent function that can be obtained by early movement of the knee, ankle and subtalar joints. Unfortunately, internal fixation is not without risk, and there is an appreciable risk of infection, which may delay union or have even worse consequences.
3 6
Surgery Vol. 1 ~/NO.
cases
followed
1
to union
Less than onehalf normal range
2 2 9
The 2 patients with established non-union in this series had both been treated by internal frxation of their fractures before coming under our care. The extent of any joint stiffness has been shown to be closely related to the severity of the fracture (Ellis, 1958) and the rate of union is almost certainly delayed by rigid internal ftxation (McKibbin, 1978). After a fracture of the shaft of the tibia, shortening of the limb may be prevented by bony contact in a stable fracture or by the intact ftbres of the damaged interosseous membrane in the unstable type (Sarmiento et al., 1974). If the fractured tibia and its related muscles are surrounded by a relatively rigid sheath of plaster-of-Paris, the limb is thought to behave as a fluid-filled cylindrical balloon. Shortening of the cylinder cannot occur without an associated increase in the diameter because fluids are incompressible, and this is prevented by the plaster-of-Paris carapace. The plaster-of-Paris cast also maintains alignment (Sarmiento et al., 1974). Sarmiento has used unpadded, below-knee, patellar-tendon-bearing plaster casts, and more recently thermoplastic braces for 482 tibia1 fractures, and has allowed full weight bearing from an early stage. In his series (Sarmiento, 1974) there were only two non-unions and the functional results appeared adequate. However, such a cast or brace is difficult to apply and the patellar-tendon-bearing factor does not appear of great importance in unloading the fracture (Posival. 1973). The method of application of our modiftcation is simple and utilizes plaster with its known excellent properties. Plaster-of-Paris avoids the skin maceration seen under thermoplastic materials. It requires little skill in application contrasting with that necessary for the correct application of a Sarmiento plaster cast. The cast also has a very smooth inner surface and therefore the skin is not at risk (Fig. 2). It provides the closest possible ftt to the limb and therefore
33
Bedford and Angel: Controlled Pressure Casting
theoretically should give the best possible control of the fracture. The results of this admittedly small series indicate that adequate control of both alignment and rotation can be obtained whilst allowing mobilization of the ankle and knee at an early stage in the treatment of tibia1 shaft fractures. Functional use may itself improve the blood supply to the limb and therefore the fracture (Trueta, 1974) and improve healing (Sarmiento, 1974). In this way ‘fracture disease’ has been avoided without the use of internal fixation. It has been especially useful in the treatment of non-union refractory to bone grafting and may prove to be a useful adjunct in the treatment of fractures by electrical stimulation.
theatre at the same hospital for their continuing help.
REFERENCES
Ellis H. (1958) Disabilities after tibia1 shaft fractures. J. Bone Joint Surg. 40B, 190. McKibbin B. (1978) The biology of fracture healing in long bones. J. Bone Joint Surg. 60B, 150. McMaster M. (1976) Disability of the hindfoot after fracture of the tibia1 shaft. J. Bone Join? Surg. 58B, 90.
R. A. (1973) A Measurement System .for Determination of Tibia1 Fracture Brace Force Diswibution. University of Miami, Department of
Posival
Bioengineering. Sarmiento A., Latta L., Zilioli A. et al. (1974) The role of the soft tissues in stabilization of tibia1 fractures. Clin. Orthop. 105, 116.
Acknowledgements
We wish to thank the orthopaedic surgeons of the Royal National Orthopaedic Hospital, Stanmore, for allowing us to report cases which were under their care, and the staff of the plaster
Sarmiento A. (I 974) Functional bracing of tibia1 shaft fractures. Clin. Orthop. 105,202. Trueta J. (1974) Blood supply and the rate of healing of tibia1 fractures. Clin. Orthop. 105, 11. Watson-Jones R. W. (1976) In: Wilson J. N. (ed.) Fracture and Joint Injuries. Edinburgh, ChurchillLivingstone, p. 1075.
Requesls for reprints should be addressed ro: Mr A. F. Bedford, Orthopaedic Department, Central Middlesex Hospital, Acton Lane, London NW 10 7NS.
PROFESSOR
WILLIAM
GISSANE
1898-l
981
Professor Gissane died on I April 1981 on the fortieth anniversary of the establishment of the Birmingham Accident Hospital, with which his name will always be linked. We are not publishing a biographical note because his achievements were fully described by the then Vice-Chancellor ofBirmingham University in Injury 10,5.